test: [fefunctional] add pytest and mark LaughFE slow&verslow

Also add note that it takes 8-10s to run a single LaughFE test

test/test_feature_extractors_functional.py

@@ -12,6 +12,7 @@ etc.
 These tests are marked slow to avoid running them during normal test runs.
 """
 
+import pytest
 import unittest
 import pipeline.feature_extractors as extractors
 import test.mocks as mocks
@@ -22,6 +23,8 @@ class FEFunctionalTest(unittest.TestCase):
     SAMPLE_DIR = "/home/robert/code/softdev2023-24/summerproject/highlights/test/sample_videos"
 
 
+@pytest.mark.slow
+@pytest.mark.veryslow
 class TestLaughterFEFunctional(FEFunctionalTest):
     """TestLaughterFEFunctional -- functional tests for laughter detection feature extractor"""
 
@@ -35,6 +38,9 @@ class TestLaughterFEFunctional(FEFunctionalTest):
                     NOTE: LaughFE subtracts from start time to capture what preceded the laughter
                     so we need to subtract this time (and adds a little after too)
                     FE 'exposes' these as _PREPEND_TIME and _APPEND_TIME
+
+        Note: takes 8-10s to run for this 30s video using GTX 970. As such this test can be skipped with either:
+              "-m 'not veryslow'" or "-m 'not slow'"
         """
         SAMPLE_VIDEO = f"{self.SAMPLE_DIR}/sample-manual-audio-laughs-video-colours.mp4"